Samsung is developing a rollable battery for wearable devices

During a trade show in Korea, Samsung SDI unveiled a new rollable battery prototype, aimed towards wearable devices. Samsung says that this is the world's first rollable battery, and they expect to mass produce such batteries within the "next few years" as they still need to improve production yields and battery stability.

LG Chem is already producing curved batteries (these are used in LG's curved G Flex phone for example), and in October 2013 LG showed their bendable "cable" batteries which seem to be similar to Samsung's rollable ones. LG also said it will take some years to commercialize this technology.